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    SubjectRe: [PATCH] fsldma: use PCI Read Multiple command

    >>>> Can you give me an example of non-PCI memory that would be
    >>>> non-prefetchable that you'd like us to try? We can see if our
    >>>> host CPUs have an area like that ... we just need to know
    >>>> what device to look for first :)
    >>> You can mark the pci inbound window on the 83xx as non-prefetchable
    >>> (assuming 83xx is host). On a x86 host I doubt there is any easy way
    >>> to get non-prefetchable memory.
    >>
    >> Yep, we were going to do that, but chose to use the
    >> 1MB region already setup for the IMMRs since its already
    >> marked as non-prefetchable. We were only doing reads, so
    >> it wasn't going to hurt anything.
    >>
    >> I doubt that marking one of the other BAR regions
    >> as non-prefetchable will give a different result.
    >> However, we're more than happy to double-check if
    >> you'd like.
    >
    > Its possible you'll get a different result since IMMR is a register
    > space internal and thats normally a completely different bus than memory
    > would be (internal to the 83xx). I'd suggest double-checking w/a BAR
    > marked non-prefetch pointing to real memory.

    We had a 4k BAR1 setup to point to DDR memory.

    With prefetchable set, a 36-byte transfer generated a
    burst-of-8 32-bit words followed by a single transaction.

    With non-prefetchable set, the transfers were all single.

    So it works like we'd expect.

    Cheers,
    Dave



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